Pfizer's one-time haemophilia B therapy Durveqtix recommended by CHMP

Pfizer's gene therapy, Durveqtix (fidanacogene elaparvovec), has received a recommendation from the European Medicines Agency's (EMA) human medicines committee for the treatment of severe and moderately severe haemophilia B in adults. The Committee for Medicinal Products for Human Use (CHMP) has suggested that this one-time gene therapy be granted conditional marketing authorisation for patients who do not possess both factor IX (FIX) inhibitors and detectable antibodies to the variant adeno-associated virus serotype Rh74.

Haemophilia B is a rare, inherited bleeding disorder that affects over 38,000 people worldwide. It is characterized by missing or insufficient levels of clotting FIX, leading to a heightened risk of bleeding. Current therapies for haemophilia B usually require regular intravenous infusions of FIX replacement products to prevent or address bleeding episodes. The EMA has emphasized the need for improved treatments that offer sustained protection against bleeding, reduce the frequency of infusions, and enhance patients' quality of life.

Durveqtix, also delivered through an intravenous infusion, is designed to enable patients to produce their own FIX. The CHMP's recommendation was influenced by positive outcomes from an ongoing late-stage clinical trial. This trial has been evaluating the annualized bleeding rate (ABR) in patients treated with Durveqtix compared to their ABR during a lead-in study period when they were on a standard FIX prophylaxis regimen.

The trial results showed that patients treated with Durveqtix had an ABR of 1.44, significantly lower than the 4.5 observed with standard prophylaxis treatment. Additionally, 60% of patients treated with Durveqtix had no bleeding events during the individual observation period, which ranged from two to four years, in contrast to 29% of patients when they were on routine prophylaxis during the lead-in period.

Patients receiving Durveqtix will be monitored for 15 years, including six years in the current trial and an additional nine years in a separate study to evaluate the long-term efficacy and safety of the therapy.

This recommendation by the CHMP, now awaiting review by the European Commission, follows the U.S. Food and Drug Administration's approval of fidanacogene elaparvovec under the brand name Beqvez for certain adults with moderate-to-severe haemophilia B, which occurred just over a month ago.

Adam Cuker, director of the Penn Comprehensive and Hemophilia Thrombosis Program, commented on the U.S. approval in April, stating that a one-time treatment with fidanacogene elaparvovec could be transformative for suitable patients by significantly reducing the medical and treatment burden over the long term.